"It was not a [targeted] malicious attack, it was a random attack," Stefanek says.

The ransomware variant used in the attack has not been named. It would likely need to be the latest variant of Cryptowall if attackers were to stand any hope of having the mind-blowing ransom paid, as many other ransomware packages contain fatal crypto design flaws.

Patients have been forced to travel an hour's drive to collect lab tests. Some reports say the hospital has reverted to fax machines for communication with the outside world.

The FBI has been called in to investigate.

Ransomware attackers have to date remained elusive. It is thought that only a small number of criminals are behind some of the most prolific ransomware malware such as Cryptowall.

Interpol has formed an international ransomware task force in a bid to identify the attackers. ®